Variable-condenser drive



Feb. 22, 1927. A. w- FRANKLIN VARIABLE cmwsnssn muva Filed Oct. 23, 1925 INVENTOR ORNEY Patented Feb. 22, 1927.

UNITED STATES 1,618,525 PATENT OFFICE.

ALBERT W. FRANKLIN, OF NEW YORK, N. Y., ASSIGNOR TO CHAS. FBAESHMAN CO. 1170.,

OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

VARIABLE-CONDENSER DRIVE.

Application filed October 28, 1925. Serial No. 64,312.

This invention relates to improvements in devices used to impart rotary motion to the rotor plates of condensers as used in radio and like apparatus.

In order to obtain the best results from such apparatus, as in tuning in, a smooth motion is desirable and preferably also a slow positive movement under the instant control of an operator.

Knob actuated, direct connected dials, while convenient and common in use, are regarded in the present state of the art, as archaic, a too rapid movement being ineilective in securing the degree of accuracy demanded in securing eiiicient manipulation of the a paratus.

.It is there ore one of the objects of the present invention to provide a device using the customary knob and a calibrated dial, but so arranged that the speed of the dial is greatly reduced in relation to that of the knob,assuring a fineness of dial setting that is highly desirable.

A further feature is in the provision of means forrotating a dial with the utmost nicety and precision, and also with absolute positiveness not attainable with friction types of drives.

Another aim is to produce a simple mechanical device for the purpose mentioned, that is inexpensive to construct and install, is of pleasing appearance, and as easy to operate as any knob controlled condenser 0 common type.

These several objects are achieved by the characteristic features of the present invention as hereinafter described, and illustrated in the associated drawing, forming an essentiol art-of this disclosure, and in which Fig. 1 is a front elevational view of an embodiment of the invention illustrating its application to a conventional type of condenser.

Fig. 2 is a side elevational view of the same, showing a fragmentary portion of a condenser, apart of the dial and supporting panel being in section.

In this drawing the numeral 5 is used to designate a mic], forming the front wall of the usual ca inet, and extending at a right anglerearwardly from the panel is a support plate 6 carrying a frame 7 in which the condenser is mounted at aspaced dis-. tance from the panel. l

The condenser, whichmay be of any ap-- proved type, consists of stator plates, generally designated by the numeral 8 and rotor plates 9, the latter being fixed on a spindle 10 in the usual manner. It is to be noted however that the spindle does not project through the panel 5.

Formed through the panel is a segmental cut out or window 11 preferably havin bevelled edges, this window registering wit the graduations 12 on a dial 13, the latter having a hub 14, fixed rigidly on the end of the spindle 10.

Said dial is circular in profile and contains a segmental opening 15 concentric with its periphery and extending in length sub- (sitarlitially one-half the circumference of the The outer edge of the openin 15 is provided nearly its full length wit teeth 16, constituting in effect an internal segmental gear, meshing with which is a pinion 17 fixed on a stub shaft 18, the outer end of which passes freely through an appropriate opening 19 in the panel 5;

The inner portion of the stub shaft 18 is reduced in diameter, as at 20, and is journalled to rotate in the arms 21, 22 of an inverted U-shaped bracket 23, the inner arm 22 of which is provided. with an elongated foot 24, secured to the upright frame 7 by screws r other fastening means '25.'

On the outer end of the stub shaft 18 is f fixed a knob, 26 of any type convenient for read twirling, and whereby the pinion is revo ved to. transmit motion directly to the dial 13, but obviously at a greatly reduced speed permitting a fine and accurate adjustment.

It will be noted that no extra gears are used, the dial itself bein pierced and one edge of the material de ning the piercing provided with teeth for cooperative engagement with a single pinion on the knob shaft which pinion projects through the piercing in the ial.

From the foregoing it will be seen that a simple device for this (purpose has been disclosed in the preferre form of its embodiment, but it is not desired to restrict the details to the exact construction shown, it being obvious that changes, not involving the exercise of invention, may be made without conflicting with the scope of the appendedclaims.

Having thus described my invention, what I tinim MW and ciesim t0 secum 133,? tars Patent, it':--

1. A mciio condenser drive comprising in combination with a variable condemer, it dial fizmii on the condenser spindle saici dial having a cuncentric openin provlc'ied with teeth on the outer edge a %racket fixed on the condenser? frame, a stub shaft rotatable in the bracket, a, pinion fixed GI} said shaft in engaga saic't teeth, and a knob w rotate said shaft.

2. A radio cenflenser dirim comprising in combinatinn with It variable condenser a dial fixed on the cundenser spindle, said ciial having a scale 0n itt face, extenfing over half its circumfsrence near the ad e, an internal segmental em integrally tormec't ilfl the pm'timi of wi dial u pnsite the male, BL pininn meshing: with mi gear, a Shaft 011 which mid; pinion is timd, mid shaft being carried by the timidlensiw frame, and Imam tom twiriing midi shaft.

3. A mim cmic'tenser drive comprising in combination with m. "variable cunc'ienser, a it cabinet and a panel atthe front thereof, said panel having a wimiow, a dial fixetl 0n the: tutor s iIHIHQ 0f midi sondenser to exposa its sen e thmugh midi windvw, an imtmrmi segmental gem farmed in said dial, a, shaft married; pinion @ngagin said gem, aninvertedi U-mhmpett bracket lied on filth Mme of snici wndtnsmr in which wiid {pinion shaft is mounted, said shaft @xixintt mg through the panel, and a knob on 'said t0 ci irectiy transmit rotation to mid 121.

Signed at New York, in. the want (it New York, and. fitmte of New York, tint fifi (My 01E Septembem ALBERT W. FRANIUJIELQ'. 

